-LRB- CNN -RRB- -- Nikolay Davydenko produced a ruthless display to beat U.S. Open champion Juan Martin Del Potro in straight sets to win the ATP World Tour Finals in London on Sunday .

Davydenko had dispatched world number one Roger Federer in the semifinals and re-produced the magic to see off the Argentine 6-3 6-4 in one hour and 23 minutes at the O2 Arena .

The victory in the elite , eight-man end-of-season showpiece is the highlight of the 28-year-old Russian 's career , going one better than 2008 when he lost in the final to Novak Djokovic of Serbia .

Davydenko , seeded sixth , had begun the week with a thrilling three-set loss to Djokovic in round-robin play , but proceeded to rack up four straight victories , culminating in his emphatic win over fifth-ranked Del Potro .

It earned him $ 1.5 million and he was delighted to have captured the first major trophy of a career marked by consistency but mostly in a support role to the game 's very elite .

`` For me it was amazing coming here number seven and winning the tournament . I surprised myself , '' he said .

Del Potro looked weary after his epic three-set semifinal win over Swede Robin Soderling the previous night .

He dropped his service in the fourth ganme of the opening set and could claim only five points on his opponent 's service as the Russian eased to an early lead .

The second set was tighter , with Del Potro having a break point in the sixth game .

But at 4-4 Davydenko made his move on Del Potro 's service .

Two blistering passing shots set up three break points and he claimed a 5-4 lead after a long rally .

Serving for the title , he set up match point with an ace and took it when Del Potro could not return a fiece smash .

It capped a week of surprises at the new venue with world number two Rafael Nadal crashing out with three straight sets defeats and home hope Andy Murray edged out of the round-robin by Federer and Del Potro by the slimmest of margins .

Soderling , who only came into the tournament as a late reserve for the injured Andy Roddick , and Davydenko were the surprise qualifiers from the other group , with the latter going all the way after beating the Australian , French , U.S. Open and Wimbledon champions .

Del Potro acknowledged he had been beaten by the better man on the day .

`` Congratulations . You are a great champion , '' he said .

Now Davydenko will eye his first grand slam title at the Australian Open in January , which will be the next major tournament test for the leading players .

Earlier , In the doubles final , American pair Bob and Mike Bryan beat Max Mirnyi and Andy Ram 7-6 6-3 to win their third ATP Finals title and claim the number one ranking in the world at the end of the season for the fifth time .

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Nikolay Davydenko wins ATP World Tour Finals title in London

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Russian beats Juan Martin Del Potro of Argentina in straight sets

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Davydenko was beaten in last year 's final by Serbian Novak Djokovic

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Bryan brothers win doubles title to claim end of season top ranking